This invention relates generally to marine deck equipment, and specifically to bitts.
The use of marine deck equipment is well known for securing marine vessels to piers with mooring lines. In particular, bitts are used by line handlers to help the line handlers pull a marine vessel alongside a pier and secure the marine vessel to the pier. After a marine vessel is pulled alongside the pier, the line handler takes several round turns of the line around the bitt, thus securing the marine vessel alongside the pier.
Conventional bitts, however, present drawbacks. For example, when drawing a marine vessel alongside a pier, the line handler must be positioned in a bent-over body position instead of an erect body position. This limits the amount of the line handler""s strength available for line-handling activities. In addition, a bent-over body position increases likelihood of back injury from line-handling activities. Further, a bent-over body position causes the hands of the line handler to be closer to the bitt than would an erect position, thus increasing likelihood of hand injury. Finally, a bent-over body position limits mobility of a line handler and reduces a line handler""s situation awareness during potentially dangerous line-handling evolutions.
Conventional bitts include a static, non-movable line-handling surface. Friction between the mooring line and the line-handling surface of the bitt results in a significant amount of the line handler""s energy being spent in overcoming friction. As a result, a significant portion of energy expended by the line handler is not translated into useful work, such as drawing the marine vessel alongside the pier.
Thus, there is an unmet need in the art for a bitt that permits a line handler to perform line-handling operations in an erect body position instead of a bent-over body position, and that permits much of the line handler""s energy to be available for useful work in line-handling activities instead of being used to overcome friction.
The present invention is a bitt with a freely rotatable line-handling surface. The bitt of the present invention permits a line handler to perform line-handling activities in an erect body position instead of a bent-over body position. Further, the freely rotatable line-handling surface included in the bitt of the present invention allows much of the line handler""s energy to be applied to useful work in drawing a marine vessel alongside a pier, instead of being wasted in overcoming line friction.
According to the present invention, a bitt includes a frame having a first side and a second side. The first and second sides of the frame each include first and second ends, and the first and second sides of the frame are substantially planar. The first and second sides adjoin each other at the first ends and define an angle therebetween. The first and second sides of the frame are arranged for being attachable to a surface of a marine vessel at the second ends of the first and second sides of the frame. First and second shafts extend outwardly from the planes of the first and second sides of the frame, respectively. The first and second shafts each have a longitudinal axis. The axis of each of the first and second shafts extends approximately perpendicularly to the plane of the first and second sides of the frame. First and second rollers each have an axis, and the first and second rollers each define a bore along the axis of the respective roller. The bores of the first and second rollers are each arranged for receiving the first and second shafts therethrough. The first and second rollers are rotatably mounted about the first and second shafts, such that the first and second rollers provide freely rotatable line-handling surfaces.
According to an aspect of the invention, the first and second rollers each have first and second end sections with a first outer diameter and a middle section with a second outer diameter. The first outer diameter is greater than the second outer diameter, such that the first and second ends of the rollers define shoulders. The shoulders advantageously prevent the mooring line from slipping off the roller.
According to another aspect of the invention, the first and second rollers are made of a slightly compressible material, such as polyurethane. The slight compressibility advantageously enables the mooring line to grip the roller and aid rotation of the roller. As a result, the mooring line does not slip along the roller, thus increasing the line handler""s control over line-handling evolutions.
According to another aspect of the present invention, the first and second sides of the frame are substantially perpendicular to each other, such that the axes of the first and second rollers each define approximately 45-degree angles with the surface of the marine vessel. As a result, the line handler is able to perform line-handling evolutions in an erect body position instead of a bent-over body position.
Thus, the line handler is able to use more body strength than the line handler could use in either a bent-over body position or standing erect when using a prior art bitt, and is less susceptible to back injuries than in a bent-over body position. Also, the hands of the line handler are further from the bitt, thus reducing likelihood of hand injuries during line-handling evolutions. Finally, by performing line-handling evolutions in an erect body position, the line handler is able to achieve a higher situation awareness during potentially dangerous line-handling evolutions than is possible when the line handler is in a bent-over body position.